Metodología del estudio de cohortes del proyecto itinere sobre consumidores de heroína en tres ciudades españolas y características básicas de los participantes / Cohort Study Methodology of the ITINERE Project on Heroin Users in Three Spanish Cities and Main Characteristics of the Participants

Fundamento: Los estudios de cohortes permiten monitorizar elimpacto del uso de drogas sobre la salud, e identificar los factorescondicionantes. El objetivo de este trabajo es describir la metodologíay las características básicas de una cohorte de consumidores deheroína diseñada con este fin.Métodos: Participaron 991 jóvenes consumidores de heroína,seleccionados en la comunidad en Barcelona, Madrid y Sevilla, principalmentemediante nominación de otros participantes (39,7%) o deconsumidores o exconsumidores no participantes (44,7%). Se administróun cuestionario con ordenador y se recogió una muestra desangre en papel secante. También se registraron sus medidas antropométricas.Se remuneró a participantes y captadores. Se usaronmétodos estadísticos uni y bivariados.Resultados: Un 42,4% había cambiado alguna vez de vía principalde administración de heroína, sobre todo hacia la inyección enBarcelona y hacia la vía pulmonar en Sevilla. Un 75,8% (Barcelona),49,8% (Madrid), y 15,5% (Sevilla) se habían inyectado drogas en losúltimos 12 meses. En Madrid y Sevilla un 96%-97% consumían laheroína sólo en forma de base, y en Barcelona predominaba la heroína-clorhidrato. Frecuentemente mezclaban heroína y cocaína en lamisma dosis (generalmente cocaína-base en Madrid y Sevilla, ycocaína-clorhidrato en Barcelona). Conclusiones: Persisten importantes diferencias geográficas enla prevalencia de inyección de drogas y en los patrones de consumode heroína y cocaína, lo que podría explicar la desigual distribuciónde algunos problemas de salud. Las dificultades para reunir la muestraprevista sugieren un descenso importante de la incidencia de consumode heroína

Background: Cohort studies make it possible to monitor thehealth impact of drug use and to identify related factors. We describethe methodology and baseline characteristics of a cohort ofheroin users designed with this objective.Methods: The participants were 991 young, community-recruitedheroin users in Barcelona, Madrid and Seville. Most subjectswere named by other participants (39.7%) or by non-participatingdrug users or ex-users (44.7%). A computer-aided questionnairewas administered (self-administered with audio for questions relatedwith sex). A dried-blood spot sample was collected and anthropometricmeasurements were made. Both participants and recruitersreceived remuneration. Univariate and bivariate statistical methodswere used. Results: Some 42.4% had changed the main route of heroinadministration, mainly to injection in Barcelona and to the pulmonaryroute in Seville. About 75.8% (Barcelona), 49.8% (Madrid),and 15.5% (Seville) had injected drugs in the last 12 months. InMadrid and Seville, 96-97% used heroin in base form, while in Barcelonaheroin hydrochloride predominated. Heroin and cocainewere frequently mixed in the same dose (generally base cocaine inMadrid and Seville, and cocaine hydrochloride in Barcelona).Conclusions: Important geographic differences persist in theprevalence of drug injection and in the patterns of heroin and cocaineuse, which could explain the unequal distribution of some healthproblems. The difficulties encountered in recruiting the sample suggestthat the incidence of heroin use has declined considerably

[Cohort study methodology of the ITINERE Project on heroin users in three Spanish cities and main characteristics of the participants]. / Metodología del estudio de cohortes del proyecto ITINERE sobre consumidores de heroína en tres ciudades españolas y características básicas de los participantes.

BACKGROUND: Cohort studies make it possible to monitor the health impact of drug use and to identify related factors. We describe the methodology and baseline characteristics of a cohort of heroin users designed with this objective. METHODS: The participants were 991 young, community-recruited heroin users in Barcelona, Madrid and Seville. Most subjects were named by other participants (39.7%) or by non-participating drug users or ex-users (44.7%). A computer-aided questionnaire was administered (self-administered with audio for questions related with sex). A dried-blood spot sample was collected and anthropometric measurements were made. Both participants and recruiters received remuneration. Univariate and bivariate statistical methods were used. RESULTS: Some 42.4% had changed the main route of heroin administration, mainly to injection in Barcelona and to the pulmonary route in Seville. About 75.8% (Barcelona), 49.8% (Madrid), and 15.5% (Seville) had injected drugs in the last 12 months. In Madrid and Seville, 96-97% used heroin in base form, while in Barcelona heroin hydrochloride predominated. Heroin and cocaine were frequently mixed in the same dose (generally base cocaine in Madrid and Seville, and cocaine hydrochloride in Barcelona). CONCLUSIONS: Important geographic differences persist in the prevalence of drug injection and in the patterns of heroin and cocaine use, which could explain the unequal distribution of some health problems. The difficulties encountered in recruiting the sample suggest that the incidence of heroin use has declined considerably.